This invention generally relates to material handling apparatus and methods. More particularly, the present invention relates to a transfer mechanism and a method for moving a laminate material from a first location to a second location.
This application is related to U.S. patent application Ser. No. 08/511,604 filed on Aug. 4, 1995 by the same applicants as the application herein and assigned to the same assignee. The subject matter of the earlier filed patent application Ser. No. 511,604 is incorporated hereinto by reference in its entirety.
Solid free form fabrication (SFF) includes automatic fabrication of functional prototypes and actual production of small numbers of engineering components. It has been determined that a three-dimensional object can be produced quite accurately by utilizing thin plane cross sections of a solid body as its building blocks with each of the cross sections being cut or formed separately. Each cross section can be cut by, for example, a laser located above a positioning or platter-like cutting table. The cut cross section is then picked up by a transfer mechanism and placed on a stack of other cross sections. Thereafter, the cross sections are attached to each other using suitable bonding techniques to arrive at a final three-dimensional product.
Cutting desired regions from individual sheets offers prospective advantages over techniques which cut, deposit or fuse material directly on top of a subassembly. These techniques include stereo lithography, selective laser sintering, three-dimensional printing and laminated object manufacturing. By cutting laminae individually, the geometric formation process is fully decoupled from the material processing steps, thus obviating the compromises which are inherent in either operation. The instant process is perhaps most similar to the so-called "Helisys" process of laminated object manufacturing in which laminated objects are formed from stacks of laser cut sheet material. The primary difference between the Helisys system and the instant invention is that the Helisys system stacks sheets first, then cuts outlines in the stacks of sheets. In contrast, the instant invention cuts each sheet individually and then stacks the sheets. Due to this difference, the instant invention more readily accommodates internal voids in multiple materials. However, this is at the expense of a more demanding material handling technique. In particular, the instant material handling technique introduces the additional complexity of extracting desired cross sectional regions from a larger sheet of laminate material after the desired cross section is cut from a sheet and the transfer of the desired cross section laminate onto a stack of other cut laminates.
The present invention contemplates a new and improved method and apparatus for material handling which overcomes the foregoing difficulties and others while providing better and more advantageous overall results.